(a) Field of the Invention
This invention relates substituted pyridine-2-hydrazines, their preparation, their salts, intermediates therefor and their use as cardiotonics.
(b) Description of the Prior Art
Lesher and Gruett British Pat. No. 1,322,318, published July 4, 1973, shows as intermediates for preparing antibacterially-active 1-alkyl-1,4-dihydro-4-oxo-7-PY-1,8-naphthyridine-3-carboxylic acids and esters (where PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents) the following illustrative reaction sequence (Examples 1C through 1G and 2C through 2G): the preparation of 1,2-dihydro-2-oxo-6-(4- or 3-pyridinyl)nicotinonitrile, its hydrolysis and decarboxylation to produce 6-(4- or 3-pyridinyl)-2(1H)-pyridinone, its chlorination with phosphorus oxychloride to produce 2-chloro-6-(4- or 3-pyridinyl)pyridine, its reaction with hydrazine to produce 2-hydrazino-6-(4- or 3-pyridinyl)pyridine and its catalytic hydrogenation using Raney nickel to produce 2-amino-6-(4- or 3-pyridinyl)pyridine, which is useful as an intermediate to produce said antibacterially-active 1,8-naphthyridines.